>Mueller also points out a fundamental difference between patent law in the US and patent law in Europe. Put simply, the patent requirements in Europe are more stringent to the extent that they are granted for technical solutions to technical problems.
So... the patent laws here are sane? Well that's a relief.
Eh ... relatively speaking. In theory, both the EPC and German law do not allow patents for software "as such".
This has been translated by the courts into a requirement that the invention have a "technical character" [1]. This means in particular that where there is a mixed software/hardware invention the inventive step has to be related to the direct manipulation of controllable forces of nature.
Initially, this was used in a fairly straightforward way. A piece of pure business software was considered to be not patentable, computer-controlled anti-lock brakes were considered patentable [2]. More generally, it had been considered to rule out practically all application programs on a general purpose computer.
However, in the decades since then, these limitations have been watered down more and more without having been officially abandoned. Examples of inventions that were categorized as patentable later was a cache algorithm (because it made more efficient use of the underlying hardware, even though that claim seemed somewhat tenuous) or a CAD/CAM program (because it allowed you to avoid constructing a prototype) [2].
While it would be correct to say that German and European patent law is somewhat more restrictive than American patent law, the inconsistent jurisprudence has created a huge gray area, which makes it difficult to predict which inventions will hold up in court and which won't. In Germany, some of the harsher critics attribute that to personnel changes at the X. Civil Senate of the Federal Court of Justice (the panel that deals with patent law cases): namely, as justices changed, the underlying theories of patentability that the court used changed and were never properly reconciled. I cannot say whether this is correct, but it would explain a lot. See also the comments by Lord Justice Jacobs in Aerotel v. Telco, paragraphs 129-131 [3] (which are about as critical as one national court allows itself to be of another: "For reasons we confess we do not fully understand the BGH considered that the case was not concerned with the computer program as such exclusion.").
So... the patent laws here are sane? Well that's a relief.